Improvement in rock-drills



UNITED STATES PATENT OFFICE.

EDWARD J. GRAHAM, OF PHILADELPHIA, PENNSYLVANIA.

IMPROVEMENT IN ROCK-DRILLS.

Specification forming part ot' Letters Patent No. 50,576, dated October24, 1865 antedated October 6, 1865.

To all 'whom it may concern.-

Be it known that I, EDWARD J. GRAHAM, ot' Philadelphia, Pennsylvania,have invented an Improved Rock-Drill; and I do hereby declare thefollowing to be a full, clear, and exact description of the same,reference being had to the accompanying drawings, and to the letters ofreference marked thereon.

My improved rock-drill is of tubular form, and has on its face sets ot'cutting-edges, arranged substantia-lly as described hereinafter, so thatthe edges of one set may strike the rock across the incisions made bythe edges ot' the adjacent set, and so that a rapid penetration of therock may be insured.

1n order to enable others to make and use my invention, I will nowproceed to describe its construction and operation.

On reference to the accompanying; drawings, which form a part ot thisspecification, Figure l is vertical section of my improved rock-drill;Fig. 2, an exterior view; Fig. 3, a view ofthe cutting endofthedrill,Fig.4,a view showing the combination of the drill with a sand-pump; Fig.5, a modilication of the cutting-edges of the drill.

The drill A is made of steel or of iron with a steel cutting end, and isof the tubular form represented in the drawings, the exterior beinglargest in diameter at the lower end, and gradually tapering to theshoulder a, and the portion b above the latter being reduced in diameterfor attachment tothe boring-bar, which may be screwed into or otherwisesecured to the drill.

In the annular face of the drill, which will be best observed onreference to Fig. 3, are cut a series ot' V-shaped grooves in such amanner as to form four sets ot" V-shaped cutting-edges, there being inthe present instance live such edges, numbered 1, 2, 3, 4, and 5, ineach set.

The cutting-edges ot' each set are arranged parallel to each other andtoa radial line drawn from the center of the face ot' the drill to theedge of the same, and the cutting-edges ot' one set are arranged atright angles to those ot' the adjacent set.

Rockdrills with V-shaped cutting edges have been heretofore made; butthe edges have been so arranged as to coincide with a series A of radiallines, in consequence of which the cutting-edges, as the'tool wasturned, invariably struck the rock in the same lines-a defeet which myarrangement ot' cutting-edges has been designed to obviate.

It will be evident that one set ot' cuttingedges cannot strike therockin the incisions previously made by another set ofthe cutting' edgesunless the rod be turned exactly onequarter round, which must be avoidedin the use ot` my improved drill, the turning of the latter being suchthat one set of cutting-edges will strike the rock in lines crossingprevious incisions made by another set. By this action ot' thecutting-edges a more rapid chipping away of the rock is insured thanwhen the edges are arranged radially.

l have found in practice that in the use ot' my improved rock-drill nocentral core ot' rock coinciding with the central opening of the drillremains, thejar of the drill and the inner cor-- ners ot' the.cutting-edges tending to shatter this central portion of the rock intosmall pieces.

The drill may be used in the simple form illustrated inthe drawings, inwhich case the detritus may be removed from time to time after thewithdrawal of the drill by the usual sand-pump; or the said pump may bcattached to and combined with the drill, the detritus passing upwardthrough the interior of the drill and through the valve of the pump, aswill be readily understood on reference to the view Fig. 4';

It will he evident that three sets only of cuttingedges, Fig. 5, may beused, and that l'or boring large holes there may be live, or even more,sets of cutting-edges.

I claim as my invention and desire to secure by Letters Patent- Thewithin-described tubular drill, having 011 its face sets ofcutting-edges, arranged sub* stantially as and for the purposedescribed.

In testimony whereot'l have signed my name to this specification in thepresence of two subscribin g witnesses.

ED WARD J. GRAHAM Witnesses:

CHARLES E. FOSTER, HENRY HoWsoN.

